Most chemical and physical processes require some degree of moisture control, with requirements ranging from super dry to supersaturated. Even those processes that require extreme dryness of the bulk material may involve water as a carrier of drying agents and other amendments. In all processing involving moisture control, rates of achieving the degree of saturation required are important aspects of processing efficiencies. Those familiar with chemical and physical processing will be immediately aware of how the invention herein described would be applicable to their needs.
Wetting agents, or “surfactants”, are typically used to “make water wetter”, i.e., to cause water to be adsorbed and/or absorbed by substrates faster and to a greater extent than is produced by water alone. The term “surfactant”, short for ‘SURFace ACTive AgeNT’, is generally used interchangeably with the term “wetting agent”. Wetting agents typically have at least two active sites, usually the opposite ends of the molecule, one hydrophilic (water-seeking) and the other hydrophobic or oleophilic (oil-seeking). Surfactants make water wetter by lowering the surface tension of the water.
Surface tension is a measure of the attraction of molecules for one another. Hydrogen bonding between water molecules is reduced by wetting agents, whose hydrophilic ends have greater attraction for water than water has for itself. Thus, water containing a wetting agent, appropriate to the solid matrix being wetted, will spread more easily over and through pores spaces of the matrix, thus permeate it faster than would normally occur.
Surfactants must be appropriate to the matrix being wetted in order to perform in the required manner. For example, surfactant molecules may react with particles, binding or precipitating the surfactant, rendering it useless. An example of this is the precipitation of soap by calcium in tap water which produces bathtub scum. Therefore, a useful formulation must employ a surfactant that prefers water, and additional agents or adjuvants/amendments carried by it, to the matrix being wetted.
Most applications of wetting agents require specific properties in addition to surfactancy, said additional properties being provided by adding additional materials to the surfactants. For example, foaming may be required, or it may be objectionable; evaporation rate may need to be fast or slow; interaction of components in the liquid phase with the solid phase may be required or detrimental; the residue left behind may be useful or objectionable to further processing, the end-use, or the environment. Optimizing properties sought for commercial, consumer, and industrial applications generally requires adding components to the wetting agent formulation that affect pH, ionic strength, and viscosity. Acids and bases; acidic, basic, and neutral salts; and organic solvents and thickeners are examples of components used to optimize the respective properties required.